For Ulysses, a Long, Fast Trip to the Sun : Science: The spacecraft will explore Earth's star from its poles, an angle scientists have never had. It will be the speediest device ever made by man.

KENNEDY SPACE CENTER, Fla. — Some photographers will do anything for the right camera angle.

The Ulysses spacecraft, scheduled to be launched aboard the space shuttle Discovery Saturday morning, will have to fly faster than any other device built by human hands, and it will have to travel nearly 2 billion miles through the back yard of the solar system to reach its destination. When it finally arrives, it will be twice as far from the sun as it was while sitting on its launching pad.

All that just so scientists can see the sun from an angle they have never seen it from before. And this will not be a portrait in the normal sense because the $750-million spacecraft does not even carry a camera. Instead, it will be a profile of the sun as transmitted by scientific instruments that can detect such factors as temperature, radiation and chemical composition.

The Ulysses, seven years behind schedule, will give scientists their first opportunity to study the sun from both its poles. And that, scientists say, should considerably advance their understanding of the star that makes life possible on Earth.

The Discovery and its five-man crew is set to carry the Ulysses aloft at 4:35 a.m. PDT Saturday.

"I've been on this project for 14 years," said Derek Eaton, project manager for the European Space Agency, which built the Ulysses. "It seems hard to believe we're about to launch."

Although scientists have been waiting for the launching for years, others hope it will never come. Several environmental organizations, including the Los Angeles-based Committee to Bridge the Gap, are trying to halt it through the courts, contending that the launching may fail catastrophically and spew plutonium into the atmosphere. A federal judge is expected to rule on the suit today in Washington.

The Ulysses will draw electrical power to run its instruments from the radioactive decay of 24 pounds of plutonium 238. Opponents of the launching say that the recent performance by the National Aeronautics and Space Administration is so poor that an accident could occur, releasing more plutonium than all the U.S. nuclear weapons tests. The opponents argue that such a disaster could result in thousands of cancer deaths.

The space agency insists that even an accident like the explosion that destroyed the Challenger would not release the plutonium because Ulysses would be blown intact out of the shuttle's payload bay.

"We could have built it" with solar power instead of plutonium, Eaton said. "But we couldn't have launched it. There is no spacecraft big enough" to have sent such a heavy payload on its way to Jupiter.

NASA did not help its tarnished image Thursday when it disclosed that workers had overlooked a nine-foot-long steel beam that had been used as a support structure for workmen inside the aft compartment of the space shuttle Atlantis. The 75-pound, bright yellow beam, which should have been removed, fell when the Atlantis was hoisted into a vertical position. The Atlantis, grounded because of a hydrogen leak, was damaged in the incident, but officials were not sure how seriously. No one was injured.